Electrochemical devices including batteries and electric double layer capacitors (EDLCs) have found great usefulness in power supplies, including power supplies of portable devices and auxiliary power supplies for automobiles. For example, lithium ion batteries are one of the most popular battery types for use in portable electronics such as phones, music players, portable computers, and so forth. Lithium ion batteries have very high energy-to-weight ratios, no memory effect, and a slow loss of charge when not in use. Lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications due to their high energy density.
The basic working unit of a lithium ion battery is an electrochemical cell. The electrochemical cell includes two electrodes, an anode and cathode that are physically separated from one another by a separator and are ionically connected to each other by an electrolyte. The anode typically includes a thin metal sheet of electrically conducting material, such as copper, which is referred to as the anode current collector and is coated with solid anode material particles. The anode particles are held to the anode current collector and to each other by an anode binder, which is typically a polymer that retains adhesion and physical characteristics such that it does not swell or disintegrate during use. Typical anode particles include graphite, or silicon-based materials or titanium materials or combinations of the three materials and optionally with some carbon black. The sizes of the solid anode particles coated on the anode current collector typically range from several nanometers to tens of microns in nominal diameter.
The lithium ion battery electrolyte may be liquid, solid or a gel. For liquid electrolytes, a separator is employed to maintain the physical separation of the anode from the cathode. A typical separator is a thin porous polymer sheet in which the void spaces are filled with electrolyte. A typical liquid electrolyte is a mixture of organic carbonates such as alkyl carbonate containing complexes of lithium ions, generally non-coordinated anion salts such as lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate monohydrate (LiAsF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), and lithium triflate (LiCF3SO3). Typical solid electrolytes are polymers. For instance, U.S. Pat. No. 7,387,851 to Gozdz, et al, describes an electrolyte formed from a liquid polymer, oligomer, or monomer electrolyte precursor that can be crosslinked to form a solid polymer electrolyte. A wide variety of materials may be used as a gel electrolyte. The electrolytes are designed to withstand the voltage between the anode and the cathode, and offer a high mobility of lithium ions without a risk of flammability.
The cathode typically employed in a lithium ion battery includes a thin metal sheet of electrically conducting material such as aluminum, which is referred to as the cathode current collector, and is coated with solid cathode particles. Cathode particles are held to the cathode current collector and to each other by a cathode binder, which like the anode binder is typically a polymer that retains adhesion and physical characteristics such that it does not swell or disintegrate during use, and the cathode binder and anode binder can be the same or can differ from one another. Typical cathode particles include lithium metal oxides such as lithium cobalt, manganese, nickel, or vanadium oxides, and other lithium compounds such as lithium iron phosphate. The cathode particles often include a small amount of carbon as well, to improve conductivity, though the carbon will generally not be as graphitic as the main carbon of the anode. The sizes of the cathode particles coated on the current collector range from several nanometers to several microns in nominal diameter.
An EDLC, also known as a supercapacitor or an ultracapacitor, is an electrochemical capacitor that has an unusually high energy density when compared to traditional capacitors. An EDLC includes two separate electrodes of the same construction separated by an intervening substance that provides effective separation of charge despite a vanishingly thin (on the order of nanometers) physical separation of the layers. The electrode of an EDLC employs a current collector, typically a current collector similar to that of a lithium ion battery cathode, such as aluminum. To improve energy storage density a nanoporous material, a porous particulate carbon such as graphite or activated charcoal is applied to the surface of the current collector with a binder, which is typically a polymer produced to retain adhesion and hardness and not swell or disintegrate during use. The particle size of the carbon generally ranges from several nanometers to several microns in nominal diameter. The pores of the carbon are filled with the intervening substance, i.e., an electrolyte that is a liquid or a gel. A typical liquid electrolyte is an organic alkyl carbonate that can include selected lithium salts.
A typical process for forming an electrode such as is found in a lithium ion battery or an EDLC includes:                1) The polymeric binding material is formed into a solution with a solvent such that the solution has a suitably low viscosity for application to the current collector after mixing with the solid particles.        2) The low viscosity binding solution is mixed with the electrode solid particles at approximately 20-80 wt. % of the solvent, and particularly approximately 50 wt. % of the solvent to form a paste.        3) The paste is coated in a thin layer (typically 10 to 200 microns) onto the current collector using conventional coating techniques.        4) The coated current collector is passed through a thermal drying oven where solvent is driven off and the binder polymer is set.        5) The electrode is passed through a pair of rotating rollers separated by a narrow gap (e.g., 5 to 200 microns) to compress the current collector coating to a specified thickness.        6) Typically, both sides of the electrode current collector are coated with the solid anode or cathode particles and processed by the aforementioned steps.        
There are multiple shortcomings involved in the manufacturing of electrodes that have a direct effect on the cost of manufacturing. These shortcomings include, without limitation:                a) Solvent used to dissolve the polymer binding material must be vaporized requiring substantial thermal energy input.        b) There are substantial energy inefficiencies associated with thermal drying.        c) The vaporized solvent must be recovered and either disposed of or recycled.        d) The oven required for drying the polymer binding material occupies significant manufacturing space at a significant capital cost.        e) The time required to manufacture the electrodes is increased by the time required for the polymer binding material to be dried in the drying oven.        
What are needed in the art are improved materials and methods for forming electrodes. For instance, improved electrode binders for use in lithium ion cathodes and anodes and EDLC electrodes would be of great use.